// 文件访问API - 提供本地上传文件的访问
import { NextRequest } from 'next/server';
import fs from 'fs';
import path from 'path';
import { lookup as mimeTypeLookup } from 'mime-types';
import { DownloadErrorCode } from '@/lib/download-errors';
import { findBlockedVideoPreviewByUrl, isVideoMediaPath } from '@/lib/video-preview-access';

export const runtime = 'nodejs';
export const dynamic = 'force-dynamic';

// GET - 获取文件
export async function GET(
  request: NextRequest,
  { params }: { params: { path: string[] } }
) {
  const pathSegments = params.path || [];

  // 健康检查
  if (pathSegments.length === 1 && pathSegments[0] === 'health') {
    return new Response('OK', { status: 200 });
  }

  const uploadDir = process.env.UPLOAD_DIR || '/app/uploads';
  const relativePath = path.join(...pathSegments);
  const normalizedRelativePath = relativePath.replace(/\\/g, '/');
  const filePath = path.resolve(uploadDir, relativePath);
  const baseDir = path.resolve(uploadDir);

  // 安全检查：防止路径遍历攻击
  if (!filePath.startsWith(baseDir)) {
    return new Response('Forbidden', { status: 403 });
  }

  if (isVideoMediaPath(normalizedRelativePath)) {
    const blockedPreview = await findBlockedVideoPreviewByUrl([
      request.url,
      `/api/uploads/${normalizedRelativePath}`,
      `/uploads/${normalizedRelativePath}`,
      normalizedRelativePath,
    ]);

    if (blockedPreview) {
      return Response.json(
        {
          error: '视频类素材上传后满 15 天才能预览和下载',
          code: DownloadErrorCode.VIDEO_WAIT_PERIOD,
          details: blockedPreview.message,
        },
        {
          status: 403,
          headers: { 'Cache-Control': 'no-store' },
        },
      );
    }
  }

  try {
    const stats = await fs.promises.stat(filePath);

    if (!stats.isFile()) {
      return new Response('Not Found', { status: 404 });
    }

    const range = request.headers.get('range');
    const contentType = mimeTypeLookup(path.extname(filePath)) || 'application/octet-stream';

    // 支持Range请求（用于视频流）
    if (range) {
      const fileSize = stats.size;
      const parts = range.match(/bytes=(\d*)-(\d*)/);
      const start = parts && parts[1] ? parseInt(parts[1], 10) : 0;
      const end = parts && parts[2] ? parseInt(parts[2], 10) : fileSize - 1;

      // 验证Range
      if (isNaN(start) || isNaN(end) || start > end || end >= fileSize) {
        return new Response('Invalid Range', { status: 416 });
      }

      const stream = fs.createReadStream(filePath, { start, end });

      return new Response(stream as any, {
        status: 206,
        headers: {
          'Content-Range': `bytes ${start}-${end}/${fileSize}`,
          'Accept-Ranges': 'bytes',
          'Content-Length': String(end - start + 1),
          'Content-Type': contentType,
          'Cache-Control': 'public, max-age=31536000, immutable',
        },
      });
    }

    // 普通请求
    const stream = fs.createReadStream(filePath);

    return new Response(stream as any, {
      status: 200,
      headers: {
        'Content-Length': String(stats.size),
        'Content-Type': contentType,
        'Cache-Control': 'public, max-age=31536000, immutable',
      },
    });
  } catch (error: any) {
    if (error.code === 'ENOENT') {
      return new Response('Not Found', { status: 404 });
    }
    return new Response('Server Error', { status: 500 });
  }
}

// HEAD - 检查文件是否存在
export async function HEAD(
  request: NextRequest,
  { params }: { params: { path: string[] } }
) {
  const pathSegments = params.path || [];

  // 健康检查
  if (pathSegments.length === 1 && pathSegments[0] === 'health') {
    return new Response(null, { status: 200 });
  }

  const uploadDir = process.env.UPLOAD_DIR || '/app/uploads';
  const relativePath = path.join(...pathSegments);
  const normalizedRelativePath = relativePath.replace(/\\/g, '/');
  const filePath = path.resolve(uploadDir, relativePath);
  const baseDir = path.resolve(uploadDir);

  // 安全检查：防止路径遍历攻击
  if (!filePath.startsWith(baseDir)) {
    return new Response(null, { status: 403 });
  }

  if (isVideoMediaPath(normalizedRelativePath)) {
    const blockedPreview = await findBlockedVideoPreviewByUrl([
      request.url,
      `/api/uploads/${normalizedRelativePath}`,
      `/uploads/${normalizedRelativePath}`,
      normalizedRelativePath,
    ]);

    if (blockedPreview) {
      return new Response(null, {
        status: 403,
        headers: { 'Cache-Control': 'no-store' },
      });
    }
  }

  try {
    const stats = await fs.promises.stat(filePath);

    if (!stats.isFile()) {
      return new Response(null, { status: 404 });
    }

    const contentType = mimeTypeLookup(path.extname(filePath)) || 'application/octet-stream';

    return new Response(null, {
      status: 200,
      headers: {
        'Content-Length': String(stats.size),
        'Content-Type': contentType,
        'Cache-Control': 'public, max-age=31536000, immutable',
      },
    });
  } catch (error: any) {
    if (error.code === 'ENOENT') {
      return new Response(null, { status: 404 });
    }
    return new Response(null, { status: 500 });
  }
}